Problem: $\dfrac{5}{-8} \div 1\dfrac{3}{7} = $
Answer: Let's start by converting the mixed number to a fraction. $\phantom{=}\dfrac{5}{-8}\div1\dfrac{3}{7}$ $=\dfrac{5}{-8}\div\dfrac{10}{7}$ $=\dfrac{5}{-8}\cdot\dfrac{7}{10}~~~~~~~\text{multiply by the reciprocal}$ $=\dfrac{{1}\cancel{5}}{-8}\cdot\dfrac{7}{\cancel{10}{2}}$ $=\dfrac{{1}}{-8}\cdot\dfrac{7}{{2}}$ $=\dfrac{7}{-16}$ $=-\dfrac{7}{16}$